Uranium Diselenide, USe₂

Uranium Diselenide, Uranous Selenide, USe₂, is formed when a current of hydrogen bearing excess of selenium vapour is passed over the double chloride at low red heat; or by fusing the same chloride with certain metallic selenides, preferably stannous selenide. It is obtained in very small black crystals, often pyrophoric. It is readily oxidised, and is vigorously attacked by nitric acid.